Apparatus for the manufacture of abrasive coatings



March 28,. 1939. c w BRYAN 2,151,737

APPARATUS FOR THE MANUFACTURE OF ABRASIVE COATINGS Filed Aug. 29, 1935INVENTOR. flies/ e1- Wflzyam,

Patented Mar. 28, 1939 UNITED STATES PATENT OFFICE APPARATUS FOR THEMANUFACTURE OF ABRASIVE COATINGS Chester w. Bryan, New York, N. Y.,assignor a Ansonia Coated Abrasives; Inc.,

Brooklyn,

N. Y., a corporation of New York Application August 29, 1935. Serial No.38,379 6 Claims. (01. 91-43) The present invention relates to devicesfor producing coatings and relates, more particularly, to devices bymeans of which abrasive coatings such as sandpaper, etc., may be formedin an improved fashion.

Various devices have heretofore been used in the manufacture ofsandpaper and kindred articles, these devices being designed with a viewto tively great speed at which their parts move, re-

15 suiting in high maintenance cost, and further by the fact that theyproduce uncontrollable air currents which tend to prevent evendistribution of the grains which form the coating.

In accordance with the present invention, it is 20 proposed to provide adevice by means of which coatings may be formed characterized by evengrain distribution.

A further object of the invention is to provide a device of the abovecharacter wherein the grains of the coating are oriented to a greaterextent and more eflectively than in existing devices.

A further object of the invention is to provide a device ofthe abovecharacter which does not produce objectionable air currents and which ischaracterized by low initial and maintenance cost.

The foregoing objects are attained, in accordance with the form of theinvention described 5 herein, by means of a mechanism which subjects thegrains to a motion under which the particles are orientated during thetravel thereof toward the surface to be coated. This motion, in thedevice described herein,'is such as to cause align- 40' ment of thelongest axes of the grains due to the action of the propelling andgravitational forces thereon, in combination with air resistance towhich the grains are subjected during their travel to the surface to becoated.

Other objects and advantages of the invention,

as well as structures by means of which the invention may be practiced,will be apparent as it is described in further detail in connection withthe accompanying drawing, wherein Figure 1 is a view in side elevationpartly in section on the line l-l of Figure 2, and looking in thedirection of the arrows, illustrating one form of mechanism by means ofwhich the present in- 55 vention may be practiced;

Figure 2 is a view in front elevation, showing the mechanism of Figure1; and

Figure 3 is an enlarged detail view of a coating which has been appliedto a surface in accordance with the present invention. 5

Referring to the above drawing, a sheet I0 is shown as travelling in thedirection indicated by the arrow in Figure 1. This sheet may be mountedupon any suitable supporting mechanism upon which the related elementsdescribed hereinafter may also be supported. Inasmuch as thesesupporting elements form no part of the present invention, thisdescription will be directed only to the elements which are necessary tocarry out the invention in the form of mechanism described herein. Itwill also be understood that the paper, cloth, or other surface to whichthe abrasive or othercoating is to be applied, is provided with acoating I i of glue prior to directing the surface under the coatingelements which will now be described.

Extending transversely of the direction of travel of the surface Ill tobe coated, is a trough or hopper l2 within which sand I3 is supplied.The trough may have a lower elongated opening through which the sand maybe discharged as desired. To facilitate the discharge of the sand,roller I5 is shown as being rotatably mounted directly beneaththeopening l4 and as rotated in the direction of the curved arrow shownin Figure 1. A gate It or other suitable device may be provided to limitthe amount of sand discharged from the trough or hopper I2, although thespecific discharging mechanism for the hopper may be varied in anydesired fashion.

The discharge mechanism (in the form shown, the roller 15) preferablydischarges the sand out-. wardly and downwardly in the path indicatedgenerally by the dot and dash lines il in Figure 1.

While the particles of sand are falling from the discharge mechanism,and before they have reached the glue-coated surface ll, they are actedupon by a plate l8 which is positioned in the path of .the fallingparticles of sand and are directed outwardly and downwardly in thegeneral path indicated by the dot and dash lines IQ of Figure 1. Thetrajectory of the particles of sand from the plate l8 may be obviouslyvaried by variation of the factors described hereinafter and, after theparticles have travelled through their trajectory, they fall upon andadhere to the coating of glue II on the surface I0. Figure 3 illustratesthe particles of sand which have adhered to the coating of glue, theseparticles being indicated at 20.

2 l 'romaninspectionofl 'igureaitwillbe seen the points ll of theseparticles extend upfrom the surface iii, the longest axes of the grainsof and extending substantially normal to such surface.

The plate II is preferably securely clamped at one end in a bracket orsimilar device 22 which may be secured upon a mounting plate II. Inorder that the plate It maystrike the grains of sand and subject them tothe proper forces, the plate is vibrated at a suitable speed in anydesired fashion. In the form shown in the accompany drawing, suchvibration is effected by means of electromagnets 24, which may bemounted upon the plate 23 and which are suitably spaced with respect tothe width of the plate II and its fixed supporting element 12. Variationof the position of the electromagnets 24 toward or away from the fixedsupporting.

bracket 22 obviously produces a corresponding variation in the effect ofthe electromagnets upon the amplitude of motion or vibration of theplate it. Such amplitude of movement may also be controlled by varyingthe electrical conditions in the circuits of the magnets. By subjectingthe electromagnets 24 to periodic electrical energizetion, the plate i8will be subjected to corresponding periodic vibrations. Obviously, byenergizing the electromagnets 24 with an alternating or other form ofinterrupted or variable current, this periodic vibration of, the plateIt may be effected, variation in the frequency of vibration beingconveniently varied by variation of the frequency of the alternatingcurrent to which the electromagnets 24 are subjected.

It will thus be seen that the plate l8 may be subjected to vibrations ofdesired amplitude and frequency, which vibrations serve to cause thegrains or sand falling through the path ll to be struck by the plate andimpelled outwardly in the path indicated generally by the dot and dashlines it. .There results a throwing of the grains of sand through a muchgreater horizontal distance and the tendency of the grains to bunch uponthe surface ill is thuseliminated. This action results in a more evendistribution of the grains in the coating and the travel of the grainsthrough the trajectory it results in a tendency of the grains to orientthemselves in such fashion as to cause them to strike the glue-coatedsurface with their longest axes vertical or, in other words, normal tothe surface I 0. The desired aligning of the grains is due to acombination of influences including the action of the propelling forces,gravity, the interaction of the grains on one another while travellingat high velocity, and air resistance to the travel of the grains fromthe plate It to the coated surface. As a result of the orientation ofthe grains, a sharper cutting type of abrasive coating is produced.

Obviously, any desired vibrating instrumentality may be used, eithermechanical or electrical. If the vibration of the plate is controlledelectrically, as in the form shown in the accompanying drawing, thefrequency and amplitude of vibration may be controlled within anydesired range in a convenient and effective manner. By varying thefrequency and/or amplitude, it is possible to control the distributionand orientation of the grains within practically definite limits, 'thusproviding for all desirable variations in size and type of grains,density of coating, and even the degree of sharpness desired in thefinished product.

It will be understood that grains thrown with too great a force mayreach their destination before they become aligned with the direction oftravel thereof, or, contrariwise, if projected with too weak a force,the herein described influences may not cause them to become so aligned.To secure best results, accordingly, there will be found to exist acritical adjustment of the grain distributing means which will producebest results for any desired type of coating. Moreover, by controllingthe vibration of the plate It electrically, and using an alternating orother variable form of current, together with means for controlling thefrequency and amplification thereof, the frequency and amplitude ofvibration of the plate It is conveniently controlled. Adjustment of theforegoing factors is found to be of advantage in correcting changingconditions such as changes in atmospheric moisture, the size and shapeof grains, the rate of flow of the sand, the speed of travel of thepaper, etc.

It will be apparent that the invention may be embodied in a mechanismwherein the coated surface may be passed above the element carrying thegrains to be applied thereto, means being provided to propel the grainsfrom the last named element upwardly to the coated surface. Such meansmay be in the form of a means for vibrating the element carrying thegrains by any suitable member.

The number of magnets may be varied as desired to give uniform vibrationthroughout the length of .the plate It and the position of themagnetswith respect to the plate may also be varied. Moreover, each ofthe magnets 24 may be controlled by a separate switch in order that thevibrating impulses may be variably applied to the plate at differentpoints and for different purposes. Refinements in the control of themagnets, for example, by varying the frequency, wave forms, andintensities of current may obviously be eflected, and the invention isnot to be limited, save as defined in the appended claims.

I claim:

1. A coating machine comprising a receptacle for abrasive particles tobe applied as a coating, means to cause the particles to fall freelyfrom the receptacle to material to be coated, and solid mechanical meansto intercept and accelerate movement of the particles while freelyfalling and in their travel from the receptacle to material to becoated.

2. A coating machine comprising a receptacle for abrasive particles tobe applied as a coating, means to discharge the particles from thereceptacle to fall by gravity, a plate in the path of the particlesfalling from the receptacle, and means to vibrate the plate.

3. A coating machine comprising a receptacle for abrasive particles tobe applied as a coating, means to discharge the particles from thereceptacle to fall by gravity, 9. plate in the path of the particlesfalling from the receptacle, and electrical means to vibrate the plate.

4. A coating machine comprising a receptacle for abrasive particles tobe applied as a coating, means to discharge the particles from thereceptacle to fall by gravity, a plate in the path of the particlesfalling from the receptacle, means to anchor one end of the plate, andmeans to vibrate the plate.

5. A coating machine comprising a receptacle for abrasive particles tobe applied as a coating, means to discharge the particles from thereceptacle to fall by gravity, a plate in the path of the means todischarge the particles from the receptacle to fall by gravity, a platein the path of the particles falling from the receptacle, means toanchor one end of the plate, and electromag 1 netic means to vibrate theplate.

' CHESTER W. BRYAN.

